Limitations in custom Keyboard Shortcuts

Unless I'm missing how to do it, the limitations on what keyboards shortcuts can be created is baffling to me. AFAIK it is still not possible to have a "Only display mask when drawing" shortcut! And today I was thinking it would be good to have a shortcut allowing me to change my color readouts (View: Lab Readout) between "None" and "LAB Adobe Generic". At first it looks like it will work, but doesn't. If I enter a key for say "Off" it is applied to all the readouts. It partly works because if I am using LAB and hit this shortcut it switches back to RGB, but I see no way to go back to LAB without going through the menu. This is just two examples of where it seems users should be able to make keyboard shortcuts.

Am I missing something and this can actually be done, or are others frustrated with the poor implementation?